Through the travel involved in this study, the investigator will determine the geographic boundaries (including the nature of these boundaries) of the multilingual area; the internal sub-patterns of this area will also be determined directly by travel. Distributions and functions of the primary (Tukana) and secondary (Spanish, Portuguese, Nheengatu or Tupi) linguae francae will be collected. Language inventories of communities and of individuals, and their roles, will be documented. Anecdotal accounts of language usages in various social situations will be kept. Individuals interviewed in prior, shorter field trips (1959-1963) will be re-interviewed. Gauges of fluency will be experimentally developed. Selected individuals will be intensively interviewed on the following factors: the "adolescent spurt" of acquiring more languages; the culturally close identification between language and "tribe" and the role of linguistic unit exogamy; and the distinctions between "father tongues" and "mother tongues." Protocols will be experimentally developed to determine degrees of "merged" vs. "coordinate" control of individual's languages with an apparent cultural predisposition for the latter. Narrow transcriptive phonological data, word lists, and grammatical materials on many (or, all) the languages in the area and many regional dialects will be collected. Methodology will be based on a previously established participant/observer role; definite questionnaires will be kept in mind as well as on paper and followed out both informally and formally. The bulk of the interviewing will be done in Tukano.